title: Prognostic implication of extrarenal metabolic tumor burden in advanced renal cell carcinoma treated with targeted therapy after nephrectomy.
abstract: OBJECTIVE
  In the era of targeted therapy for advanced renal cell carcinoma (RCC), appropriate prognosis prediction is necessary for optimal therapy with or without cytoreductive surgery. We evaluated prognostic implication of extrarenal metabolic tumor burden in nephrectomized patients with advanced RCC.
  
  
  METHODS
  Forty-four patients with advanced RCC who underwent (18)F-fluorodeoxyglucose PET/CT were retrospectively enrolled. The patients were treated with nephrectomy and targeted therapy. On PET/CT image of each patient, maximal standardized uptake value (SUVmax) of lesions were measured, and metabolic tumor burden was measured as total lesion glycolysis (TLG) by multiplying tumor volume and mean SUV. An overall TLG was calculated as the sum of those of all lesions. The prognostic value of PET parameters (SUVmax and TLG), and established major clinical factors (serum hemoglobin and corrected calcium, and number of metastatic sites) were tested with regard to overall survival.
  
  
  RESULTS
  Among 44 patients, 8 died during mean follow-up time of 21.9 ± 17.7 months. On FDG PET/CT, a total of 250 lesions were analyzed. In univariate analyses, SUVmax, TLG, number of metastatic sites, serum hemoglobin and corrected calcium were significant prognostic factors. Among them, TLG remained as an independent prognostic factor in a multivariate analysis (P = 0.038). In subgroup analyses, TLG was still a significant prognostic factor in patients treated with sunitinib only and in patients on the first staging as well as restaging.
  
  
  CONCLUSIONS
  Extrarenal metabolic tumor burden is a significant prognostic factor in advanced RCC patients treated with targeted therapy. In selection of candidates for cytoreductive surgery, the measurement of metabolic tumor burden may be effective.
authors.affiliation: Department of Nuclear Medicine, Seoul National University College of Medicine, 101 Daehak-ro, Jongno-gu, Seoul, 110-744, Korea.
authors.forename: Hai-Jeon
authors.initials: HJ
authors.lastname: Yoon
authors.forename: Jin Chul
authors.initials: JC
authors.lastname: Paeng
authors.forename: Cheol
authors.initials: C
authors.lastname: Kwak
authors.forename: Yong Hyun
authors.initials: YH
authors.lastname: Park
authors.forename: Tae Min
authors.initials: TM
authors.lastname: Kim
authors.forename: Se-Hoon
authors.initials: SH
authors.lastname: Lee
authors.forename: June-Key
authors.initials: JK
authors.lastname: Chung
authors.forename: E
authors.initials: E
authors.lastname: Edmund Kim
authors.forename: Dong Soo
authors.initials: DS
authors.lastname: Lee
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002292:Carcinoma, Renal Cell / Q000175:diagnosis* / Q000188:drug therapy / Q000378:metabolism* / Q000601:surgery; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007680:Kidney Neoplasms / Q000175:diagnosis* / Q000188:drug therapy / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D058990:Molecular Targeted Therapy; D009392:Nephrectomy; D049268:Positron-Emission Tomography; D011379:Prognosis; D012189:Retrospective Studies; D016019:Survival Analysis; D014057:Tomography, X-Ray Computed
chemical_list: D019788:Fluorodeoxyglucose F18